#include <stdio.h>
#include <string.h>
#include <stdlib.h>

int cmp(const void* e1, const void* e2)
{
    return *(char*)e1 - *(char*)e2;
}

char findTheDifference(char* s, char* t) {
    size_t sz1 = strlen(s);
    size_t sz2 = strlen(t);
    qsort(s, sz1, 1, cmp);
    qsort(t, sz2, 1, cmp);

    int i = 0;
    for (i = 0; i < sz1; i++)
    {
        if (s[i] != t[i] && s[i] == t[i + 1])
        {
            return t[i];
        }
    }
    return t[i];
}

int main()
{
    char s[] = "abhxz";
    char t[] = "hzbqxa";

    printf("%c", findTheDifference(s, t));
    return 0;
}